When a virtual machine is generated on a physical machine, a software correction patch (patch) is applied to the virtual machine, and then the virtual machine is used for operations. The patch partially corrects software.
For example, a user selects a patch to be applied. Specifically, the user selects a patch that has not been applied to the generated virtual machine from patches provided by a vendor of the software that runs on the virtual machine.
A technology exists that updates a non-running out-of-date virtual machine. According to such a technology, the virtual machine includes a plurality of software structures. The non-running out-of-date virtual machine is retrieved from a library, and is restarted on a maintenance host. The maintenance host acquires a needed software update as a patch from a corresponding update source so as to update each of the out-of-date software structures (refer to Japanese National Publication of International Patent Application No. 2009-538469, for example).
However, conventional technologies of selecting a patch have a problem of not being capable of selecting an optimal patch.
As an example, a user who is not familiar with a machine environment, including an OS and middleware, is not capable of selecting an optimal patch to be applied to the virtual machine.
As another example, the technologies for updating the non-running out-of-date virtual machine merely acquire a patch of out-of-date software and update the software, and thus, the update by the patch can cause trouble in later operations. In other words, the technologies for updating the non-running out-of-date virtual machine is not always capable of selecting an optimal patch.